In the field of nonwoven materials, there has been a continuing need for materials having high degree of flexibility and elasticity and which may be manufactured at a low cost. In particular, there is a need for an elastic material having a low elastic modulus and which retains its low elastic modulus during elongation to provide a soft, gentle elasticity. This need has persisted in spite of the fact that such materials could readily be utilized in the manufacture of a wide variety of garments of both the disposable type, such as disposable diapers, or the durable type, such as pants, dresses, blouses and sporting wear. An elastic material having a low elastic modulus and which retains its low elastic modulus during elongation would be particularly desirable for use in disposable diapers and other personal care products because articles manufactured from such materials are able to softly and gently conform to the body of a wearer and repeatedly extend and retract without creating uncomfortable pressure against the skin.
Elastic nonwoven webs of fibers have been formed from blends of styrene-poly(ethylene-butylene)-styrene elastomeric block copolymers with other materials such as, for example, polyolefins and tackifying resins to improve processing and/or bonding. While improving the processing and/or bonding properties of the elastic webs, such additives may, in certain situations, have an adverse affect on the elastic properties of the material. For example, elastic block copolymers blended with large amounts of a polyolefin and/or a low elastic modulus hydrocarbon resin may have a relatively high elastic modulus and/or may be unable to retain a desirably low elastic modulus during elongation.